Target speed calculation made easy
 

Hi mates,

I received my deluxe version yesterday and tried it for 3 hours (with 1.1 patch installed) : it's very nice IMO! Then I came to this forum and discovered that many simers were complaining about the speed calculation broken in the TDC... Even if it is a bug as it is written to work in the manual, I believe that it is fairly more realistic that way. I were always asking myself in SHIII who was the guy in my uboat who was calculating the speed estimation while I was pushing "the little button on the chronometer"... So now in SH4 with manual TDC on, we can use the chronometer but the guy who was calculating like crazy in SHIII is gone. Not a big deal IMO. We will just have to work our trigonometry again ;) .

There are several ways to do estimation of speed but I would like to present you the way I use. It's limited because it's only exact at an AOB of 90° and with the sub travelling slow. However, it is a very good estimation between 75° and 105° AOB. The interest of this method is that you do not need a calculator which would kill the immersion and that it is fast (no map drawing). You just need a "target speed estimation Table" that you can find below.

I find it to be immersive and far more realistic than the always accurate magic speed that you obtain in SHIII...

Hope it will helps some simers.

http://img115.imageshack.us/img115/3977/sh4tableoc2.jpg

lms_oid

Edited : Table modified - 30 seconds for range from 1750 to 2000 yards.

This is debatable depending on what is your impression of what are the tasks that you as a captain must do. I hope they fix this issue with chronometer for people who want to keep it simpler.

But this table is quite useful regardless, thanks.

It would be cool if you could make a few tables for different common AOBs. Like one for 45 and like 25 or something. You could have a few charts. Hell you could just give us the equation involved in that chart and we could all make our own custom ones.

Me personally I'd make one for every say 10 or 15 degrees. Probably need fewer too as you get closer to 90.

I'd think map plotting would be easier. Take a range and bearing of the target, start clock and mark it on the map. Wait a minute and repeat. Use the ruler to measure the distance travelled. Now you have time and distance, calculating speed is easy after that...granted it requires we have bearing info as a map plotting tool. I have yet to play the game so thats something im not sure we have. But if it is, its accurate under all conditions.

I missed the Nagato battleship I was aiming at and instead hit a carrier far behind.

Sorry, It seems that none of us newbies can elaborate exactly how much we need the Auto Speed Determination of the chronometre to even get started using a manual tdc. Because the issue is this simple: We cannot hit anything of what we are aiming at. As in, nothing, maybe by luck, if I crazily enough manage to determine the speed, by a wild guess, then maybe I hit once or twice.

Right now, It would be easier for me to put everything on Zero on the TDC, and just aim ahead of the enemy ship I`m shooting at, and simply develop a feel for how many clicks in the periscope, ahead, of the enemy ship, I have to shoot, to get a hit.
But for real.. Who had time and resources enough to practice that.. that person would not be a sub captain for long..


S! to all


SK

Don't get me wrong, I totally understand that people want this bug to be solved. I just find that it's very realistic as this and I love it.

Yes, this way is good too. You only have to multiply the distance travelled in one minute by 60 to have the actual speed. Depending on the speed you may have to wait a little longer though. By waiting 3 minutes between the two checks, you only have to multiply by 20... And it is a lot of fun to draw that on the map (very immersive IMO).

The formula I use is only true at an AOB of 90 because it use trigonometry. The exact formula is :

1 yard = 3 feet
1 nm = 6080 feet
1 hour = 3600 seconds

BC = Bearing Change in degrees
S = Speed in knots
R = Range in yards (given by the stadimeter)
T = Time between the to bearing checks in seconds

S = (tan BC x 3 x R x 3600)/(T x 6080)

However, the more your AOB is far from 90° (more or less), the more the speed is underestimated by this table so you can guess that adding x knots to the estimated speed would be a good idea.

lms_oid

After thinking it through and recalling all the old ways of getting target info in SH3, I still dig the functionality of the nomograph.

In SH3 if I needed speed I could take the range, mark it on the map, run the stopwatch for any period of time (longer the better) and then apply those numbers to the nomograph and get a solid speed out of it. And it works at any AOB.

If the stadimeter in SH4 is better than the one in SH3 then range shouldn't be an issue. That means that all you need is time, and thats a number that you can generate yourself.:up:

But I dig the charts anyway. I want to work out a chart system that can spare me the need of a nomograph under as many circumstances as I can avoid.

Thanks for the table! :up:

Nomograph?? what the heck is that? :P (yes, i'm green but wanna learn) ;)

Why would the good old 3min 15sec method not work in US subs ?

I want the nomograph in SH4 asap. Is there any way to get it in?

Loved it in SH3..

This is Wazoo's nomograph mod for SH3

http://i4.photobucket.com/albums/y13.../findknots.jpg


The 3 lines at the bottom is the nomograph. If you know any 2 values of the 3, you can discover the 3rd unknown value. If you know time travelled, and distance travelled, you can find speed. If you know speed and time travelled, you can find distance. All you need to do is make a line between the 2 known points, and the line will cross the 3rd line where you will find the value you were looking for.
Quite ingenious.

Imperial metrics? However, if you have more than one minute, drawing the all thing on map should be the better way. The table I made is more intended for fast solution building when you have to fire quickly.

lms_oid

Right ! but then if now distances on the map are in nautical miles like it should be, it makes things even easier as you don't need the nm/km conversion anymore... Distance travelled in 3mns x 20 = speed in knots.

Exactly what I said :D !

lms_oid

i try again and again but the numbers are just way off. Cant hit anything.

S!

RH

Try the third mission of the naval school. You should find a speed of 9 knots for your target. In order to find this result you must :

- Identify the ship in the recognition manual and validate in order to send the mast high which should be aroud 75 to the Stadimeter.
- If this is correctly done, you should find a range of about 1000 yards with the stadimeter. Validate this info to send it to the TDC.
- Set the angle of bow to 90° on the right (which is approximately the case) and send again the info to the TDC by validating.
- Check the bearing and launch the chronometer for 10 seconds. You should note a bearing change of about 3° during those 5 seconds.
- By using the table I provided, you can see that the speed of the target for 1000 yards / 3° should be 9 knots. Set the target speed to 9 knots and validate to send the info to the TDC.
- Congratulations : You have entered a valid solution in the TDC!
- Launch the tropedo and it WILL hit!

Remark 1 : By playing this mission with manual TDC disable, you can see that the speed of the target IS 9 knots, so if you find 9 knots manually, you are right!

Remark 2 : Don't forget to VALIDATE (by clicking on the button) each info you gather or you enter in order to send it to the Stadimeter or the TDC. If you don't do that, the TDC won't be updated with information you've gathered and the torpedo will go everywhere but not on your target.

lms_oid

First of all a thanks to lms_oid for this lovelt table. I'm sure that it'll come in handy and I will definitely try this out. :up:

Would you believe that I've looked and looked and looked again at those lines and never knew what they were there for? :doh: I feel so silly at some times. :nope:

Much to learn, this young one has ... hmm? :yep:

I cant get any bearing change on the position follower unless i input a speed value in the tdc. Besides there are no numbers, only small little lines. So I cant even count it accurate. Sorry for the trouble, and thank you for answering so quick earlier, I guess I am just getting frustrated by this issue, having to spend 2 days to learn other methods of getting somewhat accurate speed and aob into the tdc is a pretty steep learning curve, and sure does cause alot of stress.

S!

RH

Don't be frustrated, everybody has to learn and I don't know many games where you have this kind of work to do (IMO, SH manual TDC is really realistic).
If 10 seconds is to short, you can still use the formula I gave earlier with T=30 seconds or more. But by zooming (mouse wheel) and by locking the target using 'L', you should be able to estimate the bearing change for 10 seconds.

lms_oid

rgr. I think I found a way to determine bearing,
First I find the mogami in the recognition manual, input it to the tdc.
then I went to the map, and drawed a line from the Mogami`s stern to maybe 100 meters in front of it. Then I took the Compass, and clicked in 30 yards away from the end of the "100 yard" line, which the Mogami will reach within x amount of time, and i expanded it, and then made it so it pointed against my sub. Then I took the protractor at the exact end of the 100 yard line and to the 30 yard away from end. and then to my sub, I had a value of about 63 degrees to his Starboard. Which is then, AOB, then I hurried up and got range and speed into the TDC.

I repeated the above AoB trick I just did, and thus, I managed to calculate AoB within 30 seconds. Which was about 3 degrees in 30 seconds, give or take.

Finally! All 4 torpedoes hits at exact same place on the Cruiser, and he goes down quick!


Thanks alot for the solution :D

S!

RH